Examples: Aldehydes and ketones

1. Examples: Aldehydes and ketones

2. Add quickly Conditions for Alpha Substitution

3. Conditions for Carbonyl Condensations

4. “Condensation” drives the overall reaction (notice equilibrium arrows)

5. Synthesis: Two products can be formed by the aldol

6. Symmetrical vs. Mixed Aldol

7. Example: Single product mixed Aldol No acidic protons

8. Example: Single product mixed Aldol These protons are more acidic, thus easier to remove

9. Watch out for the possibility of mixture of products In this case no mixture… why? – stability of pdt

10. Example: Mixed Claisen No acidic hydrogens

11. Example: Mixed Claisen-“like” A mixed aldol – Claisen type reaction

12. Example: Intramolecular Claisen

13. Intramolecular Claisen: Application to Synthesis • The β-keto ester formed still has one acid hydrogen and thus can do additional chemistry. • Remember, the β-keto ester formed can be hydrolyzed to the β-keto acid and these can spontaneously decarboxylate.

15. Review: Synthesis of an enamine

16. Enamine’s react similar to enolates

17. Example: Stork Reaction

18. Example: Robinson Annulation

19. Biological Claisen

20. Glucose Biosynthesis (Gluconeogenesis)